This invention relates to the art of providing a portable climbing apparatus for bird watchers, tree surgeons, window washers, high-rise rescuers and the like and has particular relationship to portable facilities enabling a user to set up the apparatus at a site and in a position which he feels is best for his purposes.
Typical prior art apparatus include a chair and a platform connected to a hoist having handles which the user operates to raise himself. A major disadvantage of this approach to hoisting oneself is that the upper body strength required of the user is tremendous and well beyond the strength of an average individual.
Devices having a frame which arches generally upwardly behind a seat member upon which a rider sits to crank foot pedals are also known in the prior art. Among these devices are Snyder's orchard lift disclosed in U.S. Pat. No. 4,174,022 and Mannesmann's workman's seat disclosed in British Pat. No. 1,074,649. In the former, two sets of legs support a socketed bridge on which is rotatably mounted a hemisphere; the upper end of a frame, to which are attached a seat member and a foot-pedal operated winch, slides upwardly and downwardly within a sleeve on the hemisphere as a hoisting cable attached to it is alternately retracted and extended. By so restricting the travel of the frame, Snyder can avoid any interference between the foot pedals and the ground or having the winch, which is positioned lowermost on his frame, become enmeshed in dirt and debris. Mannesmann, on the other hand, offers no structure to keep the foot pedals from coming in contact with the ground. Rather Mannesmann relies on the stability provided by a pair of lateral arms which extend horizontally at the height of a seat member from behind it and forwardly on either side of it so that a would-be user need not rest the device on its lowermost parts, including the pedals and cranking mechanism, in order to mount the seat member. Neither Snyder's limiting structure nor Mannesmann's lateral arms are suitable to stabilize a portable climbing device which must either rest on the ground or on nothing while a rider attempts to mount it because the object to be scaled is substantially taller than the frame of the device and lacks a face against which to support a pair of lateral arms.
It is the object of this invention to overcome the above-mentioned disadvantages and to provide a portable apparatus for establishing an elevated position to and from which an operator can easily raise and lower himself, respectively.